Flexible member



N. E. LEE

FLEXIBLE MEMBER `July 3, 1951 Filed Feb. 21, 1946 FIGS.

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IN VEN TOR. NORMAN E.. LEE

l ATTORNEY Patented `luly 3, 1951 FLEXIBLE MEMBER Norman E. Lee, Forest Hills, N. Y., assignor to the United States of America as represented by the Secretary of War 'Application February 21, 194s, serial No. 649,448

12 Claims. (Cl. 267-1) (Granted under the act of March 3, v1883, as

rrlce amended April 30, 1928; 370 0. G. '757) The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to me of any royalty thereon.

The present invention relates to exible memshown in the drawings, wherein bersand is particularly directed to such mem- Figure 1 is an elevational view of a motor 13ers as are adapted to be used in antenna masts vehicle type antenna mast base embodying the and the like, as disclosed and claimed in my copresent invention; pending application forpatent on improvements Figure 2 is an enlarged fragmentary vertical in Antenna Mast Base, filed on February 11, sectional view of the mast base of Figure 1 show- 1944, and bearing Serial No. 521,964 which was ing the parts in unflexed condition; and issued on September' 9, 1947, as Patent Number Figure 3 is a further enlarged view similar to 2,427,08. Figure 2, except that the flexible `member is Innumerable devices in many arts incorporate shown in a flexed condition as might be caused flexible members of one kind or another. Exby deflections Vof the antenna mast during use` amples cf such flexible members are flexible cou- Referring now more particularly to the drawplings for the transmission of power, tachometer ings, the antenna mast base shown therein incables, multiple conductor electrical cables carcludes a support insulator Ii, a lower socket I3 rying current to moving units, flexible hose for secured to said insulator II, a flexible sheath I5, liquids and many others. Another application, secured to said lower socket I3, an upper socket and one which will be used in the present case Il secured to the upper end of said flexible sheath for purpose of illustration, is the base for an I5, an outer cover 23 surrounding said sheath I5, antenna mast installed on a motor vehicle or an antenna [errule I9 secured to the upper socket watercraft. Il and a sheaf of spring wires 2I extending be- Most flexible members of the prior art are so 25 tween the lower and upper sockets I3, I1 and constructed that they have one or more weak Within the flexible sheath I5. points where breakage is likely to occur long be- The lower socket I3 is a cylindrical metal cup fore the balance of the structure has outlived its which 1 is provided with a cylindrical, ccaxially usefulness.l The construction of some members disposed, bore 25 facing upwardly. The upper allows nonuniform flexibility throughout their end of said socket I3 is circumferentially rablengths which is objectionable for some uses. beted to form a relatively thin, upwardly ex- Again other `flexible members cause electrical tending, tubular flange 2'I of less outside diamefects, either capacitive or inductive, which make eter than the balance of the socket I3 and an them highly unsatisfactory .in some applications, upwardly facing exterior circumferential shoulsuch as an antenna mast base. der 28. The lower end of the upper socket I1 is It is therefore an object of the present invenprovided with a similar bore 25 and is likewise tion to provide a flexible member which is not eircumferentially rabbeted to form a similar subject to undue strain at any point and theretubular/ ange 2l, which extends downwardly, fore is less liable to breakage. l y and asimilar shoulder 28, facing downwardly. It is a further object to provide a flexible mem- A plurality of juxtaposed spring wires 2 I, such ber wherein the degree of flexibility is substanas lengths of piano wire, extend into the bore 25 tially constant throughout its length. of the lower socket I3 at one end and into the It is still another object to provide such a bore 25 of the upper socket Il at the other end. flexible member in which electrical disturbances The lower ends of said wires 2I are secured to are eliminated or at least reduced to a minimum. each other and into the bore 25 of the lower It is yet another object to provide a flexible socket I3 by Welding or any other suitable means. member which is durable and capable of sus- Said spring Wires 2|, hOWeVefy throughout the taining the shocks and vibrations ordinarily incibalance of their lengths are free to slide longident to its use. tudinally against one another when subjected to It is still another object to provide a flexible bending. -The upper ends of the spring wires 2I member which may be utilized as an electrical do not extend completely into the bore 25 of the conductor. upper socket I'I, thereby allowing sufficient room A further object is to provide a flexible member for sliding, within said upper socket, upon deflecwhich is relatively light in weight and inextion. pensive to fabricate. The flexible sheath I5 is made up of a tightly These and other objects will become apparent from the following description of one embodiment of the present invention'which is exemplied in the structure hereinafter described and maybe used in the spring 29.

For compactness and reduced weight, the inner surfaces of the tu'rns of the helical spring 29 are preferably flattened out slightly, by grinding or otherwise. After such flattening, the .inside diameter of the helical spring29 should equal the inside diameter of the tubular flanges 21. The opposite ends of said spring 29 surround the tubular flanges 21 of the lower and upper sockets I3, I1 and abut the shoulders 28 thereon. 'Ihe inner surfaces of a number of turns 3| at both ends of said helical spring 29,I which surround said anges 21, are suitably flattened, to a greater extent than throughout the intermediate portion of said spring, by grinding or otherdamping the motions of the antenna and curtai-ling extreme gyrations thereof.

During such flexure of the assembly, successive turns of the spring 29, on the Voutside of the bend, will separate some to allow the turns of soft wire 33 therebetween to move slightly inwardly between -said turns, and successive turns of the spring 29, on the inside of the bend, will move closer together and will force the intermediate of the helical spring 29, on the outside of the wise, to allow them to encompass said tubular anges 21. Said turns 3| are preferably attened internally so that they are approximately semicircular in cross section. After such flattening the inside diameter of said end turns 3| should be equal to the outside diameter of the tubular flanges 21. This allows them to encircle the flanges 21 and also gives them increased flexibility, the importance of which will become apparent hereinafter. V

Four strands of soft wire 33 are wound about the helical spring 29 and are staggered relative to the turns of said helical spring 29, so that the turns of soft wire 33 are forced into the interstices between the successive turns of the spring 29 and push said successive turns of the spring 29 apart slightly. When so constructed said turns of soft wire 33, when in place, in cross section, are flat on the outside and have two concave surfaces on the inside to allow intimate intermeshing with the turns of the helical spring 29. After the soft wire 33 has been forced into place, the spacing between successive turns of the spring 29 should preferably be approximately the same as the spacing between successive turns of the soft wire 33.

The opposite ends of the exible sheath I5 (made up of the spring 29 and the soft wire 33) Y are secured to the lower and upper sockets I3, I1 by means of two tubular sleeves 35 which are slipped respectively over the sockets I3, I1 so as to extend partly over said sockets I3, I1 and partly over the opposite ends of said sheath I5. The said sleeves 35 are swaged into tapered indentaticns 31 ground into the sheath I5 and into the sockets I3, I1 at several points about their peripheries. Said sleeves 35, in addition. may be brazed or soldered tothe ends of the sheath I5 and to the sockets I3, I1. y

The entire fiexible assembly Iis then embedded in and surrounded by a cover 23 of elastic material, such as real or synthetic rubber, which cover shouldY completely encase the i exible sheathV I5, the sleeves 35 and portions Vof the sockets I3, I1. Y f

In the operation of the device just described, when the assembly is flexed in any direction (as shown in Figure 3), the spring wires 2| will flex and, except at their lower anchored extremities, will slide lengthwise along each other. The sheath I5 should preferably surround said bundle of wires 2| with sufficient snugness so that the wires, in sliding against each other, set up a certain amount of friction therebetween, 4thus bend, to pull apart to a greater extent than the heavier intermediate turns of said spring 29.

'Ihis protects said heavier turns from undue strain at the crucial points of the assembly, namely at the ends of the tubular flanges 21 and prevents breakage at these points. It also prevents gaps between successive turns in the sheath I5 at these points, which gaps would upset the continuity of electrical contact between turns and give rise to harmful electrical disturbances in some applications.

It is to be noted that the tubular flanges 21 should preferably be of sufficiently thin metal so that they are suflciently flexible so that theycan assume a somewhat oval configuration in cross section during flexure of the wires 2| to better facilitate such fiexure.

Although the 'fiexible member herein is illustrated in the drawings in connection with a plurality of spring wires 2|, it will be understood that it can be used in other applications, such as where the interior is hollow, as in gasoline hose and the like.

Although the spring wires 2| of the illustrated embodiment are anchored Ain one of the sockets I3, it will be understood that they need not be so anchored, but may be individually free to slide back and forth longitudinally. It is merely necessary that the distance from the blind end of the bore 25 of one socket I3, I1 to the blind end of the bore 25 of the other socket be somewhat longer than the spring wires 2| so as to allow said wires to bend freely when the assembly is flexed.

Since many changes may be made in the above construction and many apparently widely different embodiments of this invention may be -made without departingY from the scope thereof,

it is intended that all matter contained in the above description or shown in the accompanying' vwhich encircle the anges so as to be weaker in l extension throughout said end portions, and said helix of soft wire being wound around said spring and of similar pitch and disposed in the interstices between the turns of said spring.

2. In a flexible member as defined in claim 1, wherein a plurality of spring wires extend longitudinally within the flexible sheath and partly into the sockets.

3. In a flexible member as defined in claim 1, wherein a plurality of spring wires extend longitudinally within the flexible sheath and partly into the sockets and wherein the flanges are flexible.

4. In a flexible member a pair of spaced opposed sockets, tubular flanges on said sockets extending toward each other, a, helical spring extending between said sockets and encircling said flanges, the turns of the spring encircling said flanges and immediately adjacent said flanges being less stiff than the balance of said spring.

5. In a flexible member as defined in claim 4, a helix of soft metal wound about the spring and intermeshed into the interstices thereof.

6. In a flexible member as defined inclaim 4, a helix of soft metal wound about the spring and intermeshed into the interstices thereof so as to force the turns of said spring into spaced relationship.

7. In a flexible member as defined in claim 4, wherein the tubular flanges are flexible.

8. In a flexible member, a pair of cylindrical spaced opposing sockets, tubular flanges respectively on said sockets facing toward each other. a helical spring extending between said sockets and encircling said flanges, a helix of relatively soft wire wound around said helical spring and wedged into the interstices between successive turns thereof, the spring being of less cross sectional area and less stiff throughout its end portions which encircle the flanges than throughout the balance of its length, means for anchoring the opposite ends of the helical spring and the helix of soft wire to the sockets.

9. A flexible member as defined in claim 8, wherein the sheath is surrounded by a cover of elastic material.

10. A flexible member as Ydefined in claim 8, wherein a plurality of juxtaposed spring wires extend longitudinally through the interior of the spring.

11. In a flexible member as defined in claim 8, wherein the flanges are flexible.

12. A flexible member as deflned in claim 8, wherein a plurality of juxtaposed spring wires extend longitudinally through the interior of the spring and wherein the flanges are flexible.

NORMAN E. LEE.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS 

